scalar-tensor theories

Scalar-tensor theories are alternative models of gravity that extend Einstein's General Relativity by including an additional field called a scalar field. While General Relativity describes gravity using the curvature of spacetime created by mass and energy, scalar-tensor theories add a scalar (single-value) field that influences gravitational interactions. This extra field can vary across space and time, potentially explaining phenomena like the universe's accelerated expansion or differences in gravitational behavior not accounted for by Einstein's theory alone. These theories aim to provide a broader framework for understanding gravity, which can be tested through observations and experiments.